The present invention relates generally to air filtering devices and, more particularly, to fresh air supply devices for heating, ventilating, and/or air conditioning installation in a motor vehicle.
Motor vehicles have been known to have fresh air inlets. Air flowing through these inlets may have particulate matter entrained therein. It is desirable to remove this particulate matter prior to applying the fresh air flow to the heating, ventilating, and/or air conditioning apparatus of the motor vehicle.
German Pat. No. 1,188,458 provides a device wherein a filter is provided to separate small droplets contained within an inwardly directed airstream. However, if the fresh air flow contains moisture entrained therein also, the useful life of the filter will be significantly reduced or it will be necessary to employ more expensive and durable filter elements. To further reduce both assembly and maintainance costs, it is desirable to provide a simplified and readily accessible filter assembly.
It is therefore an object of the present invention to provide an improved fresh air supply installation for use in motor vehicles.
Another object is the provision of a vehicle fresh air supply having an improved means of filtering particulate matter as well as entrained moisture from the air flow.
A further object is to provide a vehicle fresh air filtering device which exhibits a long useful lifetime and is easy to install and/or replace.
Yet another object is the provision of a vehicle fresh air filtering device which is self-cleaning.
Still another object is to provide a means for preventing moisture entrained in the air flow from being admitted to the dust filter of a vehicle fresh air installation.
These and other objects of the present invention are attained in the provision of a fresh air supply device disposed beneath the fresh air inlet of the vehicle hood and including a channel oriented transversely with respect to the air flow for receiving water flowing off the hood and/or windshield, a relatively coarse mesh grill downstream from the channel for retaining larger particulate matter entrained in the fresh air flow, a downwardly pointing ledge extending from the grill and into an air collecting tank for precipitating entrained moisture and deflecting air flow, and a dust filter at least partially covered by the downwardly pointing ledge and arranged in an oblique position with respect to the air flow such that dust trickling off its dirty side falls freely downward.
Water running off the windshield and entrained as drops by the airstream collects in the channel and flows downward externally and laterally with respect to the air collecting tank. In the following grill, larger impurities in the form of leaves, for example, are retained, while even smaller moisture droplets contained in the airstream are precipitated on the ledge in the course of the deflection process, so that the air which reaches the dust filter is very largely moisture-free. The dust still contained in the air is deposited on the filter surface and, due to the particular installation position of the air filter, can fall freely downward at times of low air throughput and due to vibrations and then be discharged together with the separated water.
The fresh air supply installation of the present invention may be formed into a unitary modular subassembly insertable under the vehicle hood. This subassembly would include the channel, grill, ledge, and dust filter as well as a base outlet which descends, self-centeringly, into a discharge chuck in communication with the open atmosphere. Such a modular subassembly could simplify both initial installation and replacement.
A large effective filter surface is obtained if the dust filter is constructed as a multiply folded paper filter, preferably with vertically oriented folds.
Embodiments of the present invention also include a partition which extends between the channel and the grill to form a filter cover. Upon removal of this partition, the dust filter is extractable for replacement or repair.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.